Modular concrete floatation unit

ABSTRACT

A modular floatation unit useful in the construction of floating piers, boat houses, work platforms, docks, marinas, and the like, readily articulated and of particular utility in water bodies with frequent level changes. The modular floatation unit is comprised of the combination of a reinforced concrete channel slab having an upper flat side and a hollow or concave side, blocks of cellular foam or plastic wrapped in a protective covering or coated with a protective film packed within the hollow or concave side of the said slab, and an open wood frame secured to the underside of the concrete slab to hold the wrapped or coated blocks of cellular foam or plastic in place. The center of gravity of the modular floatation unit is located at a point wherein, in water, the upper flat side of the concrete slab will float above the surface, and provide a deck or walkway as well as protection for the wrapped blocks of cellular foam or plastic. The wood frame will be submerged where it will protect the blocks of cellular foam or plastic against impacts, and it is itself protected against deterioration.

United States Patent 1 1 Gonzalez 1 Dec. 18, 1973 MODULAR CONCRETEFLOATATION UNIT [76] Inventor: Paul S. Gonzalez, 12258 Buckingham Ave.,Baton Rouge, La.

221 Filed: Aug.9, 1971 21 Appl. No: 169,968

l14/O.5 F, 0.5 T, 45, 46, 230, 66 SF, 65 A, 26, 43.5; 9/8 R, 8 P;61/465, 48, 46; 14/27,

[56] References Cited UNITED STATES PATENTS 3,276,209 10/1966 Mosdelll14/0.5 F X 3,579,680 5/1971 McLean ll4/O.5 F 2,860,801 11/1958 Nielsenl 9/8 R X 3,012,533 12/1961 Tellefsen..... ll4/0.5 F 3,131,665 5/1964Kiekhaefer.. 114/665 F 3,152,568 10/1964 Mayer 1l4/0.5 F 3,323,4796/1967 Filak 1l4/0.5 F 3,581,505 6/1971 Liddell 61/46 3,616,774 11/1971Thompson. 1l4/0.5 F 3,654,885 4/1972 Godbersen 1l4/0.5 F 3,659,5405/1972 Toby et a1. 1l4/O.5 F 3,665,882 5/1972 Georgieu et a1 ll4/O.5 F

Primary Examiner-Trygve M. Blix Assistant ExaminerBarry L. KelmachterAttorney-Llewellyn A. Proctor [57] ABSTRACT A modular floatation unituseful in the construction of floating piers, boat houses, workplatforms, docks, marinas, and the like, readily articulated and ofparticular utility in water bodies with frequent level changes. Themodular floatation unit is comprised of the combination of a reinforcedconcrete channel slab having an upper flat side and a hollow or concaveside, blocks of cellular foam or plastic wrapped in a protectivecovering or coated with a protective film packed within the hollow orconcave side of the said slab, and an open wood frame secured to theunderside of the concrete slab to hold the wrapped or coated blocks ofcellular foam or plastic in place. The center of gravity of the modularfloatation unit is located at a point wherein, in water, the upper flatside of the concrete slab will float above the surface, and provide adeck or walkway as well as protection for the wrapped blocks of cellularfoam or plastic. The wood frame will be submerged where it will protectthe blocks of cellular foam or plastic against impacts, and it is itselfprotected against deterioration.

15 Claims, 6 Drawing Figures 1 .&

PAIENIEDnu: 18 ms sum a of 2 INVENTOR. RAUL s. GONZALEZ BY C,

MODULAR CONCRETE FLOATATION UNIT Various floatation units, includingbuoyant structures of modular form, have long been known for use in theconstruction of floating piers, boat houses, work platforms, docks,small craft, yacht or boat marinas, and the like. Many of these unitswere constituted of hollow, box-like units which depended largely on theenclosed void to provide buoyancy. The materials of construction used informing these units have been quite varied. A considerable number offloatation units were made of metal, but corrosion problems wereburdensome and impacts sometimes damaged the units beyond repair. Earlyfloatation units were also made of wood and the floatation unit, thoughinitially heavy, further lost buoyancy by becoming water logged.Problems existed in sealing joints, and the wood deteriorated and wasinfested by marine organisms, borers, and fungi. Wooden planks formingthe deck of such structures were subject to attack by moisture, boardsloosened and nails rusted. Nails tended to pull out as the planks warpedand twisted due to moisutre and weathering. Periodic scraping, sanding,painting and replacement of boards was necessitated. A high degree ofmaintenance was thus required to keep the wooden structures inserviceable condition.

With the more recent advent of cellular forms and plastics, somefloatation units were constructed of blocks of these materials, e.g.,cellular polystyrene. These materials, however, had the disadvantage offriability which causes them to spall and the material can be easilyrubbed away as when in contact with a shifting pier. Cellular forms canalso become encrusted with barnacles, and the material is easily damagedwhen the barnacles are removed. Such materials are also readily attackedby acids, corrosives, detergents, and organic solvents, such asgasoline, which are often present around piers and docks due to spills.Attempts have been made to provide both the wooden and the cellularplastic materials with waterproof skins, but the problems were retainedonce punctured by impacts, e.g., from boats, as happened all toofrequently.

Floatation units constructed of reinforced concrete have also been usedin the art with some degree of success. Despite its excessive mass andrelatively low tensile strength, concrete was recognized as a relativelyinexpensive construction material. Moreover, it is very desirable andhas the advantage of being highly resistant or impervious to attack bymarine organisms, fungi, borers, corrosion and chemicals. Its weight hasbeen overcome by the use of relatively light-weight aggregates, such asperlite, pumice, expanded shale and expanded clay. The use of wire meshand reinforcing rods has alleviated the lack of tensile strength.Nonetheless, present concrete floatation units also suffer a number ofserious disadvantages. An acute disadvantage is that great care mustthus be exercised during shipment and in the positioning of the floatsto assure against cracking or other structural damage. If any smallholes are made in any of the concrete structures, water will fill thehollow center and cause the floats to sink. This hazard obviouslyremains even after the floats are shipped and positioned, due topotential impacts.

It is accordingly the primary objective of the present invention toprovide a new, improved and highly durable floatation unit, or module,which will obviate the foregoing and other prior art disadvantages.

It is an object to provide such floatation unit, or module, of simplestructure which can be used to support other structures or floatedsemi-free by use of standard anchor methods.

It is an object also to provide means for linking together a pluralityof such floatation units, or modules, to form piers, boat houses, workplatforms, and marinas for use by yachts, small craft, boats and thelike.

A particular object is to provide floatation units, or modules, ofsimple and relatively inexpensive construction, particularly structuresof such character which readily lend themselves to rapid mass productiontechniques.

These and other objects are achieved in accordance with this inventionwhich embodies improvements in floating modules wherein reinforcedconcrete, cellular foams and plastics, and wood are each used in theconstruction to their best advantage. A modular floatation unit,particularly an articulated modular floatation unit, is comprisedgenerally of a precast reinforced concrete channel slab, the hollow orconcave side of which is packedwith a cellular form or plastic,preferably coated or wrapped in a protective film or covering, thelatter being secured in place by a wood frame, or frames, attached tothe concrete slab.

In assembled position, the center of buoyancy is such that the precastreinforced concrete channel slab constitutes the upper portion of amodular floatation unit and the flat side thereof is floated out of thewater, providing a floor surface or deck. The buoyancy for the modularfloatation unit is provided by the cellular foam or plastic. Attack byacids, corrosives, detergents, organic solvents, and the like, isprevented in major part by the protective cover or film, and partly bythe surrounding concrete. Immiscible solvents, such as gasoline, whichfloat on the surface of the water often cannot contact even theprotective film or cover of the cellular foam or plastic because of thesurrounding layer of concrete. An open wood frame, or frames, is boltedor otherwise attached upon the bottom of the precast reinforced concretechannel slab to hold the wrapped cellular foam or plastic within thehollow or concave side of the slab while the module is out of the water,as during construction. Since the wood frame, or frames, constitutes thebottom of the modular floatation unit and lies totally submerged in thewater, there is little or no deterioration as is common when wet wood isalternately wetted and dried. Further, the protective wood frame andconcrete shields the cellular foam or plastic so that it cannot spall orrub away by contact with other objects as when the floatation unit comesinto contact with stumps and similar objects due to fluctuating waterlevels.

This type of construction is relatively inexpensive and readily lendsitself to rapid mass production techniques. For example, the reinforcedconcrete channel slab is precast at a factory site in precisely the samemanner as a slab built for roof constructions except for side openings.The slabs can be shipped, assembled into modules, and the modules thenput together to form piers, docks, marinas, and the like, without majorconcern of cracking or creation of holes such as can producecatastrophic consequences with prior art type concrete floatation units.At the module assembly site the cellular or plastic foam can be wrappedin protective covers, placed within the hollow or concave side of theconcrete slab and the wood frame, or frames, attached to the slab tohold the floatation material in place.

The invention, and its principle of operation, will be more fullyunderstood by reference to the following detailed description of aspecific embodiment, and to the attached drawings to which reference ismade in the description. In the description, similar numbers are used torepresent similar parts or components, and subscripts are used wherethere are a plurality of similar parts or components.

In the drawings:

FIG. 1 is a top plan view of improved floatation units or modulesembodying the present invention, including a fragmentary view of similarfloatation units or modules to which the former are attached;

FIG. 2 is a side elevation view of the preceding figure;

FIG. 3 is a section taken along lines 33 of FIG. 1 showing the interiorconstruction of the floatation units or modules;

FIG. 4 is a front end view of one of the floatation units or modules,this figure also showing certain details of construction, and the mannerin which modules can be fitted together in parallel or side-by-siderelationship;

FIG. 5 depicts in enlarged fragmentary section the manner in whichmodules can be fitted together or attached in end-to-end relationship;and

FIG. 6 is an enlarged side elevation view of the forward end of a moduletaken along lines 66 of FIG. 1 showing certain details and the manner inwhich the module is floated.

Referring to the figures, particularly to FIGS. 1 and 2, there is showna series of interconnected floatation units mo modules l0,,l0 ,10 ,ll0which can be linked or secured one to another in end-to-end andside-byside or parallel relationship one to another to form a floatingstructure, e.g., a pier. Float modules 10 ,10 and float modules 10 ,10respectively, are connected or bolted together in side-by-siderelationship one to another to form a portion of the pier, and floatmodules 10 ,10 are connected together in end-to-end relationship withfloat modules 10 ,10 Virtually any number of the float modules can belinked together in end-toend or side-by-side relationship to form shapessuch as Ts, L's, Us, rectangles and the like, consistent with practicalconsiderations, and with the strength of the concrete and the structuralrequirements of the steel rods used to link the members together,particularly in side-by-side relationship. Suitably, 10 to 20, or more,of the float unit are linked together in end-to-end relationship and asmany as 10 to 12, or more, in side-byside relationship. The exact sizeand shape of the units can be readily varied to meet the plan of theconstruction, as can the relative location between the floatation unitsthemselves whether staggered or in series.

It will be observed that the top portion of a floating module 10, orportion thereof, which floats above the water level is constructed of aprecast reinforced concrete channel slab 11 ,11 the flat side of whichforms a walking surface or deck. Dock cleats or other such devices canbe provided to which ropes or lines can be fastened so that yachts orsmall boats can be moored alongside the pier or floating structure. Aninwardly sloped forward wall 12 ,12 and vertically oriented end and sidewalls 13 ,14 ,14 respectively, of the concrete portion of a floatationmodule 10 join together in a parallelogram, each wall intersectinganother at right angles, and each extending downwardly into the water.At the center of the module 10 the side walls 14 ,14 are perpendicularlyjoined through a vertically oriented inner wall 15 so that twocompartments 16 ,17 are formed within the hollow or concave side of aconcrete channel slab 10 Galvanized steel reinforcement, e.g., steelreinforcing rods (not numbered), and wire mesh are located within theconcrete channel slabs 10 for added strength, as required by structuralconsiderations, and openings (not numbered) are out within the sidewalls 114 to reduce the weight.

The compartments 16,17, e.g., compartment 17 of a module 10 are tightlypacked with one or more blocks 18 of cellular foam or plastic,especially a monocellular foam such as Styrofoam, to provide buoyancy,and the blocks of Styrofoam are coated, wrapped or painted with asuitable protective film or thin cover which prevents attack by acids,corrosives, detergents, organic solvents, and the like.

The wrapped blocks of Styrofoam 18 are held in place within compartment17 of module 10 by a wood frame 19 which is bolted or otherwise securedto the underside of the said module 10 e.g., by bolts 20 ,21 Preferably,the wood frame 19 is pretreated with a preservative under pressure,e.g., as when pretreated under pressure with creosote in conventionalmanner. Creosote treated wood frame 19 will last almost indefinitelyunder water out of contact with air. The location, in the modularstructure, of the concrete, the wrapped cellular plastic foam, and thewood is ideally suited to maximize the advantage of each of theindividual units for the good of the whole. The total module has theadvantage of reinforced concrete in the location where it is mostneeded, viz., to shield against impacts, to provide optimum mass forshock absorption, and also to provide maximum durability against theaction of the elements and normal environmental conditions. The plasticfoam is an integral part of the modular unit and provides optimumbuoyancy. It is protected by the surrounding layer of concrete but yetit offsets the major disadvantage of concrete, viz., its excessive mass.The open wood frame, on the other hand, is also highly durable whenbelow water. It protects the cellular plastic from impacts from below,where some impacts can be expected, particularly at the time thestructure is first placed in water. The structure is open to ingress andegress of water, differing basically from prior art floatation unitswhich were destroyed by holes or cracks sufficient to permit ingress ofwater such as would destroy the buoyancy of the structure.

The forward wall of a module 10, including both the wall of precastreinforced concrete channel 12 and the forward wall of wood frame 19, issloped inwardly and both the sloped forward end of a module 10 and theopposite end are provided with a plurality of aligned eye bolts 22,23through which a rod 24 can be passed to secure modules 10 in end-to-endrelationship.

Reference to FIG. 5 there is illustrated a preferred method in whichfloat modules 10 ,10 can be secured together in end-to-end relationshipwhile yet permitting some relative motion between the modules as can beexpected from ordinary wave action. A rod 25 is thus passed through eyebolts 23 ,24. which are affixed upon float modules 10 10 respectivelyand paired with other similar eye bolts. The end or head of the rod 25is threaded and an enlarged screw cap 26, threadably engaged therewith,prevents accidental removal of the rod 25. In the series, a forwardsloped wall is paired with a vertical wall to permit free upward anddownward motion by the modules, as when they are influenced by waves, sothat they do not come into contact one wall with the other.

In a pier construction it is also generally necessary to secure a numberof the modules together in side-byside relationship, thus providing awide surface or deck area, and a platform which is highly stable againstwave action. Typically, the modules are fastened together via bolts27,28 and the outside faces of the modules of a series is normallyprovided with wood rails 29 ,29 which serve as bumpers.

It is apparent that various modifications and changes can be made in thestructure without departing from the spirit and scope of the presentinvention. Changes can thus be made in the absolute or relativedimensions of the parts, materials used, and the like, as well as in thesuggested mode of securing the component parts of the individual moduletogether, or in attaching the individual modules themselves together toform a floating pier, boat house, work platform, dock, marina, or thelike.

The concrete slabs can be precast in conventional manner, and reinforcedwith ordinary welded wire mesh or concrete reinforcing rods, or both.Ordinary concrete or lightweight concrete aggregates which include,e.g., perlite, pumice, expanded clay, expanded shale, and the like, canbe used in the formation of the precast concrete slabs. The lightweightconcrete aggregates are preferred.

Cellular or plastic foam of various types is widely known in the art,these being characterized by their very low weight per unit volume andclosed cell structure. In this invention, monocellular foam is used, andit is preferably used in the form of rigid blocks. Exemplary of suchfoam materials are polyurethane, polystyrene, and the like. Styrofoam, apolystyrene foam of monocellular structure manufactured and sold underthe Dow Tradename, is a particularly suitable material because it ishighly impervious to penetration by water, even after extremely longperiods of exposure. The blocks of cellular or plastic foam are coated,wrapped, or painted by a protective film or cover which is waterproofand impervious to most corrosives, acids, detergents and organicsolvents. Illustrative of such materials are polyethylene,polypropylene, polyvinylidene chloride, and polyvinyl chloride.Polyvinyl chloride sold under the Ethyl Tradename Visqueen isparticularly useful in this capacity.

Virtually any wood is found useful in the formation of frames for use insuch constructions, notable amont which is pine.

Having described the invention, what is claimed is:

1. A modular floatation unit useful in the construction over water offloating piers, boat houses, work platforms, docks, marinas, and thelike, comprising the combination of:

a reinforced concrete channel slab having an upper flat side, a maximumof two parallel aligned side walls secured to the edges of said upperflat side, 6

enclosing end walls and up to one intermediate wall providing a box-likemember with a hollow underside, said side and end walls extending belowthe surface of said water when said floatation unit is floated, and anopen bottom,

cellular plastic foam packed within and completely filling the hollowunderside of said reinforced concrete channel slab, and

an open wood frame secured to the under-side of the concrete channelslab which holds the cellular plastic foam in place within the hollowunder-side of the concrete channel slab,

the center of gravity of the aggregate structure which is located atsuch point that the flat upper surface of the concrete channel can befloated above the surface of the water, while the wood frame lies totally submerged in the water.

2. The apparatus of claim 1 wherein the wood frame is pretreated with apreservative to suppress deterioration due to fungi or other livingorganisms.

3. The apparatus of claim 1 wherein the cellular plastic foam iscomprised of blocks, and the blocks are wrapped with a protective filmsubstantially unreactive to acids, corrosives, detergents, organicsolvents, gasoline and the like.

4. The apparatus of claim 3 wherein the blocks of cellular plastic foamare of monocellular structure.

5. The apparatus of claim 3 wherein the protective film is polyvinylchloride.

6. The apparatus of claim 1 wherein the reinforced concrete channel slabconstituting a portion of the modular floatation unit is precast, andprovided with end walls and side walls, the latter containing openingswhich lessen the mass of the said slab.

7. The apparatus of claim 6 wherein a plurality of the modularfloatation units are secured together in parallel relationship by boltswhich are passed through the side walls of adjacent units.

8. The apparatus of claim 6 wherein each of the end walls of the modularfloatation unit is provided with a plurality of spaced-apart eye boltsthrough which a bar can be passed to secure a plurality of modularfloatation units together in series.

9. The apparatus of claim 8 wherein an end wall of the modularfloatation unit is sloped inwardly and the opposite end wall isvertically oriented.

10. The apparatus of claim 9 wherein a plurality of the modularfloatation units are secured together in end-to-end relationship viapassage of a bar through the said spaced-apart eye bolts.

11. A modular floatation unit useful in the construction over water offloating piers, boat houses, work platforms, docks, marinas, and thelike, comprising the combination of a reinforced concrete channel slabwhich includes an uppe flat side, a maximum of two parallel aligned sidewalls secured to the edges of said upper flat side, enclosing end walls,and an intermediate inner wall in parallel relationship to said endwalls which divides the underside of the channel into two compartmentsin tandem relationship one with regard to the other, said side and endwalls extending below the surface of said water when said floatationunit is floated,

blocks of cellular plastic foam packed within and completely filling thetwo com-partments on the under-side of the said reinforced concretechannel slab, and

open wood frames secured to the under-side of the concrete channel slabover each of the compartments to hold the blocks of cellular plasticfoam in place within said compartments within the concrete channel slab,

the center of buoyancy of the modular floatation unit being located suchthat the flat upper surface of the concrete channel can be floated abovethe water to provide a deck surface, while the frames are totallysubmerged within the water.

12. The apparatus of claim 11 wherein the reinforced concrete channelslab is precast, and the side walls thereof are provided with openingswhich lessen the mass of the said slab.

13. The apparatus of claim 11 wherein the blocks of cellular plasticfoam are wrapped with a protective plastic film substantially unreactiveto acids, corrosives, detergents, organic solvents, gasoline, and thelike.

14. The apparatus of claim 11 wherein the outside face of each end wallof the modular floatation unit is provided with a plurality ofspaced-apart eye bolts through which a bar can be passed to secure aplurality of the modular floatation units together in series, one endwall of the modular floatation unit is sloped inwardly and the oppositeend wall is vertically oriented.

15. The apparatus of claim 11 wherein a plurality of the modularfloatation units are bolted together in parallel via bolts which passcompletely through the width of the said units.

1. A modular floatation unit useful in the construction over water offloating piers, boat houses, work platforms, docks, marinas, and thelike, comprising the combination of: a reinforced concrete channel slabhaving an upper flat side, a maximum of two parallel aligned side wallssecured to the edges of said upper flat side, enclosing end walls and upto one intermediate wall providing a box-like member with a hollowunderside, said side and end walls extending below the surface of saidwater when said floatation unit is floated, and an open bottom, cellularplastic foam packed within and completely filling the hollow undersideof said reinforced concrete channel slab, and an open wood frame securedto the under-side of the concrete channel slab which holds the cellularplastic foam in place within the hollow under-side of the concretechannel slab, the center of gravitY of the aggregate structure which islocated at such point that the flat upper surface of the concretechannel can be floated above the surface of the water, while the woodframe lies totally submerged in the water.
 2. The apparatus of claim 1wherein the wood frame is pretreated with a preservative to suppressdeterioration due to fungi or other living organisms.
 3. The apparatusof claim 1 wherein the cellular plastic foam is comprised of blocks, andthe blocks are wrapped with a protective film substantially unreactiveto acids, corrosives, detergents, organic solvents, gasoline and thelike.
 4. The apparatus of claim 3 wherein the blocks of cellular plasticfoam are of monocellular structure.
 5. The apparatus of claim 3 whereinthe protective film is polyvinyl chloride.
 6. The apparatus of claim 1wherein the reinforced concrete channel slab constituting a portion ofthe modular floatation unit is precast, and provided with end walls andside walls, the latter containing openings which lessen the mass of thesaid slab.
 7. The apparatus of claim 6 wherein a plurality of themodular floatation units are secured together in parallel relationshipby bolts which are passed through the side walls of adjacent units. 8.The apparatus of claim 6 wherein each of the end walls of the modularfloatation unit is provided with a plurality of spaced-apart eye boltsthrough which a bar can be passed to secure a plurality of modularfloatation units together in series.
 9. The apparatus of claim 8 whereinan end wall of the modular floatation unit is sloped inwardly and theopposite end wall is vertically oriented.
 10. The apparatus of claim 9wherein a plurality of the modular floatation units are secured togetherin end-to-end relationship via passage of a bar through the saidspaced-apart eye bolts.
 11. A modular floatation unit useful in theconstruction over water of floating piers, boat houses, work platforms,docks, marinas, and the like, comprising the combination of a reinforcedconcrete channel slab which includes an uppe flat side, a maximum of twoparallel aligned side walls secured to the edges of said upper flatside, enclosing end walls, and an intermediate inner wall in parallelrelationship to said end walls which divides the underside of thechannel into two compartments in tandem relationship one with regard tothe other, said side and end walls extending below the surface of saidwater when said floatation unit is floated, blocks of cellular plasticfoam packed within and completely filling the two com-partments on theunder-side of the said reinforced concrete channel slab, and open woodframes secured to the under-side of the concrete channel slab over eachof the compartments to hold the blocks of cellular plastic foam in placewithin said compartments within the concrete channel slab, the center ofbuoyancy of the modular floatation unit being located such that the flatupper surface of the concrete channel can be floated above the water toprovide a deck surface, while the frames are totally submerged withinthe water.
 12. The apparatus of claim 11 wherein the reinforced concretechannel slab is precast, and the side walls thereof are provided withopenings which lessen the mass of the said slab.
 13. The apparatus ofclaim 11 wherein the blocks of cellular plastic foam are wrapped with aprotective plastic film substantially unreactive to acids, corrosives,detergents, organic solvents, gasoline, and the like.
 14. The apparatusof claim 11 wherein the outside face of each end wall of the modularfloatation unit is provided with a plurality of spaced-apart eye boltsthrough which a bar can be passed to secure a plurality of the modularfloatation units together in series, one end wall of the modularfloatation unit is sloped inwardly and the opposite end wall isvertically oriented.
 15. The apparatus of claim 11 wherein a pluralityof the modular floatation units are bolted together in parallel vIabolts which pass completely through the width of the said units.